For example, JP-2003-042754-A proposes a vehicle controller capable of diagnosing a steering angle sensor. The vehicle controller judges that the steering angle sensor is abnormal when the angular velocity calculated from the output value of the steering angle sensor exceeds an allowable maximum angular velocity.
In the above-mentioned vehicle controller, when the calculated angular velocity even once exceeds the allowable maximum angular velocity, the steering angle sensor is judged as abnormal. Hence, the steering angle sensor may be misjudged as abnormal, even when the angular velocity becomes more than the allowable maximum angular velocity temporarily due to noise or the like (even when the angular velocity becomes more than the allowable maximum angular velocity momentarily but then returns to its original value), for example.